1. Field of the Invention
The present invention relates to a novel composition for the treatment of boiler water and to a method of treating boiler water. More particularly, it relates to a boiler water treatment composition human health, has excellent stability, can be used as a liquid formulation having anticorrosion activity (activity of eliminating oxygen) or both of anticorrosion activity and antiscale activity and exhibits enhanced anticorrosion activity by increasing concentration of sulfite ion which is an oxygen scavenger.
2. Description of the Prior Art
Various kinds of oxygen scavengers for example hydrazine and sodium sulfite, have heretofore been used for prevention of corrosion in boilers. However, hydrazine has a drawback that it has a safety issue for human health. Sodium sulfite has drawbacks that its concentration in a solution tank is decreased by reaction with dissolved oxygen because of excessively large rate of reaction with oxygen and corrosion is not effectively inhibited or may even be accelerated because of the resultant insufficient addition and that a large amount of a solution of the compound has to be added to a boiler because the amount of the compound dissolved into the solution is limited when the compound is dissolved together with an alkali agent, such as sodium hydroxide and the like, or a polymer to form a liquid composite and this situation causes problems such as alkali corrosion and carrying-over because of excessive addition of the compound or the alkali agent. There is also known a method in which an agent containing an organic polybasic acid having two or more carboxyl groups is used for treatment of boiling water in a boiler in combination with sulfite (Japanese Patent Application Laid-Open No. 1992-232285). However, this method has the same drawbacks as those described above caused by using the sulfite.
Boiler water treatment compositions containing organic oxygen scavengers have been used to replace the aforementioned agents. However, these compounds have a drawback that measurement of residual concentration of the oxygen scavenger is difficult and the amount of addition of the composition is not easily adjusted in such a manner that concentration of the scavenger compound is always kept at the optimum value.